so we always on the defensive, with so much limitation. >> let me interrupt, only because we're running out of time. the sandals versus the shoe steer was when you dropped your south vietnamese people dressed in the black pajamas in the north. >> mm-hmm. >> c.i.a.-led, c.i.a.-generated, and you said the c.i.a. misread the fact when they dropped people in in the north they had shoes on, but the north vietnamese wore sandals. >> yeah, well, what we learn later is that, you know, under the communist system, they recognized people and trained the people and have very tight and very effortly system to control, you know the people. so when a new foreigner infiltrate in their hamlet village, if you don't pay attention to the detail, you know, even your accent and the way you eat, you know, they will recognize right away that you are infiltrating, yes. >> unfortunately, we're without out of time. there's a lot more we weren't able to talk about. nguyen cao ky, the author, former prime minister of south vietnam. the book is >> were on the national mall in washington at the international book fes